The present invention relates generally to devices or determining the incoming direction of incident light and, more particularly, to devices that determine the incoming direction of incident light over a sector using a relatively small number of optical elements.
In a number of situations, it is desirable to know the direction of incidence of light from a light source. One such situation arises in the entertainment arena. It is often desirable for a virtual reality simulator to include a light detector that determines the direction of incoming light. Current virtual reality systems typically involve the use of complicated positional detectors that follow relatively complex focusing or alignment procedures.
One such position detector employs a photodiode or charge-coupled device (CCD) array having multiple discrete sensing elements. Another such position detector uses a slit positioned to direct the incident light onto different optical elements depending on the angle of incidence of the light. In this system, Gray-coded multi-element arrays assess the angle of incidence of the laser light. While devices of this nature do provide positional information, they have a number of disadvantages. For one, they provide directional information or resolution about only one axis, which is aligned with the slit, and therefore, two such devices are necessary to provide dual axis resolution. Further, the detector's accuracy is dependent on the amount of optical elements in the arrays and, if CCD elements are used in the array, the detector's dynamic range is inherently limited. In light of the above, such devices are relatively expensive and complex.
Another positon detector employs a variety of separate discrete elements, each of which corresponds to a different angle of incidence of the light. The detector has a large number of elements, each of which is sensitive to a particular azimuth and elevation in the context of a polar coordinate system. Such a detector, if it is to provide high resolution, necessitates a relatively large number of optical elements, since its accuracy is directly proportional to the number of elements utilized. However, due to, among other things, the amount of detectors involved, and the electrical system that processes and analyzes the positional information furnished by the optical elements, such systems are relatively expensive and complex.
It should, therefore, be appreciated that there exists a definite need for a relatively simple and cost effective device that can determine incoming direction of incident light from virtually any direction within a hemisphere or sphere without a large number of optical elements or complex processing electronics. The present invention addresses this need.